/Engine/Source/Runtime/Core/Public/Internationalization/Text.h
The primary consumer of this type is Blueprints (via a UHT mirror node). It isnotexpected that this be used in general C++ asFFormatArgumentValueis a much better type. The UHT struct is located here: Engine\Source\Runtime\Engine\Classes\Kismet\KismetTextLibrary.h
struct FFormatArgumentData
FString
ArgumentName
FText
ArgumentValue
double
ArgumentValueDouble
float
ArgumentValueFloat
ETextGender
ArgumentValueGender
int64
ArgumentValueInt
TEnumAsByte<EF...
ArgumentValueType
This is a non-unioned version ofFFormatArgumentValuethat only accepts the types needed by Blueprints It's used as a marshaller to create a realFFormatArgumentValuewhen performing a format